The Otterbox 2000 is a near perfect fit for the Nokia 770. I found my at Ballard Camera in Seattle for $16US.

Here's some fuzzy pix of mine:

http://kgfowler3.home.comcast.net/images/otter1.jpg
http://kgfowler3.home.comcast.net/images/otter2.jpg

cheers,
-kf